Field of the Invention
The present invention relates to a damping force variable type shock absorber, and more particularly, a damping force variable type shock absorber which implements a soft damping force to improve a ride comfort by bypassing a working fluid while allowing a deformation according to a flow of the working fluid in a predetermined speed section.
Description of the Related Art
In general, shock absorbers are used in vehicles so as to improve ride comfort by absorbing and damping a vibration or shock which is transferred from a road surface to an axle during driving.
Among these shock absorbers, a damping force variable type shock absorber operates according to a vibration of a vehicle based on a state of a road surface and varies a damping force according to an operating speed.
In such a conventional damping force variable type shock absorber, an auxiliary valve is installed so as to provide a soft damping force during a high-frequency stroke.
A conventional auxiliary valve includes a connection passage formed in a piston rod, a housing connected to the piston rod under a piston valve, and a spool installed to be vertically movable in the housing.
The auxiliary valve may generate a soft damping force by an operation of opening and closing a passage through a vertical movement.
However, the conventional damping force variable type shock absorber may generate a contact noise due to a shock caused by the vertical movement of the spool, and its structure may become complicated due to a large number of parts, resulting in an increase in a manufacturing cost.